ASNT Level III- Visual & Optical Testing

Macroetching is the use of chemical solutions to attack
material surfaces to improve the visibility of discontinuities
for visual inspection at normal and low power magnifications.
Caution is required in the use of these chemicals—the use
of protective clothing and safety devices is imperative. Test
object preparation and the choice of etchant must be appropriate
for the inspection objectives. Once the desired etch is
achieved, the metal surface must be flushed with water to
avoid over etching.
Charlie Chong/ Fion Zhang